Rotary fluid coupling and thermostatic control therefor



March 17, 1953 P. P. NEWCOMB 2,631,432

ROTARY FLUID COUPLING AND THERMOSTATIC NTROL. REFOR ed May 1949 ML M Patented Mar. 17, 1953 ROTARY FLUID COUPLING AND THERMO- STATIC CONTROL THEREFOR Philip P. Newcomb, Manchester, Conn., assignor to United Aircraft Corporation, East Hartford, -Conn., a corporation of Delaware Application May 21, 1949, Serial No. 94,705

8 Claims.

' This invention relates to a device for controlling the temperature of the Working fluid of an hydraulic coupling.

A problem encountered in the use of hydraulic couplings for transmitting power is that of maintaining the temperature of the working fluid within limits which will prevent damage to any of the coupling parts. One or more small bleed holes venting the coupling chamber directly to the exterior of the coupling usually are provided on the periphery of the coupling casing to allow a circulation of fluid through the coupling. Under ordinary operating conditions, these bleeds are suflicient to prevent the temperature of the fluid within the coupling chamber from exceedin a safe limit.

However, under certain conditions such as operation at high slip or operation when the driven member overrides the driving member, heat is generated within a coupling faster than it can be dissipated and the temperature of the fluid will increase quickly with the possibility of damage to the coupling parts.

A feature of this invention is a temperature responsive device which will permit the working fluid to be discharged from the working chamber of an hydraulic coupling at an accelerated rate when overheating occurs.

A feature of this invention is an improved and simplified device for limiting the maximum temperature of the working fluid of an hydraulic coupling.

Another feature of this invention is a temperature responsive valve for controlling the rate of flow of the working fluid to an hydraulic coupling to assist in cooling the coupling when overheating occurs. 7

Other features and advantages will be apparent from the specification and claims and from the accompanying drawing which illustrates an embodiment of the invention.

- In the drawing,

Fig. 1 is a cross-sectional View of the hydraulic coupling showing the temperature responsive device for controlling the rate of fluid flow through the coupling and the temperature responsive device for controlling the rate of fluid flow to the coupling.

Fig. 2 is an enlarged section of the ring and the annular groove in the hydraulic coupling casing showing the passage formed when the ring is in its expanded position.

Fig. 3 is a detail view of the pin which prevents the ring from rotation relative to the hydraulic coupling casing.

Referring to the drawing, hydraulic coupling 2 is supported by shaft 4 within casing 5. This coupling consists of impeller B rotatable on shaft 4 and driven by gear 8, and runner Iii which drives gear I2. The runner will be caused to rotate with the impeller when working fluid is admitted to chamber [4. The coupling 2 has a ports being in axial alignment with the center of groove l8.

Ring 28 has bleed holes 3E! located about it A circumference, these bleed holes being of a smaller diameter than casing ports 28 with which they align. A pin 32 is provided on the left face of ring 20, this pin cooperating with radial groove 34 (Fig. 3) in member 22 to prevent rotation of the ring relative to the coupling casing. This permits bleeds 3!] to be maintained in alignment with ports 28, but does not interfere with radial expansion of the ring. By means of the bleed holes, fluid is permitted at all times to drain from coupling chamber :4 thus insuring a circulation of fluid through the coupling which will prevent overheating under normal operating conditions. The ring is sufficiently narrower in width than groove l8 so that passages 36 and 38 (Fig. 2) are formed on either side of the ring.

Ring 20 is constructed of a material having a greater coeflicient of expansion than the material from which coupling l5 and member 22 are constructed and, therefore, will expand at a greater rate than will casing I6 upon an increase in temperature. The ring is designed to fit tightly in the root of the groove under normal operating conditions. As the temperature of the coupling increases, this ring will move away from the root of the groove to permit additional flow of fluid from the coupling through ports 28 and clearance passage ll (Fig. 2), formed by the difference in expansion between the ring and the casing, and through passages 36 and 33 at the sides of the ring to the exterior of the coupling. Tabs could be provided if desired at intervals along the faces of the ring to assure its being centrally located within the groove l8, but this feature is not considered essential.

For introducing working fluid to the coupling, casing 5 has a conduit 42 in line with shaft 4. The fluid passes through variable restriction 4i, passage 46, and radial ports 48, to annulus 551 from where it passes into the coupling chamber [4 by means of passage 52. Fluid flow to the coupling may be regulated by means of a valve not shown, the supply of fluid within the cham ber l4 determining the amount of power being transmitted by the coupling impeller to the cou pling runner.

The variable restriction 44 is operated by solenoid 54 which is part of electrical circuit 56. A bimetallic switch 58 is provided in this circuit,

the switcnbeinglocated within. casing at some. point near the-periphery of coupling 2 in order that its elements 6!] and 62 will be subject to thefluid being discharged from the coupling through bleeds 3i], and passages 36 and 38. The elements of this switch are so constructed that when fluid being discharged from the coupling reaches a predetermined maximum temperature; they. will move together to close contact 64 completingcircuit 55 and energizing solenoid. 54. When the. solenoid is energized, valve 44 will be moved up ward to decrease the effect of the restrictionzin passage 42 and allow a greater quantity of fluid to flowinto and through the coupling. Since this fresh supply,- of, fluid will be at a lower tempera.- ture. than the fluid in the chamber l4, it will result in;a reduction of thecoupling temperature to; a. safe operating limit.

It. is to be understood that the invention is notglimited: to. this specific. embodiment herein illustrated and described, but may be used in other ways. without departure ironrits spirit as defined. by the following claims.

What-it: isdesired. to secure by Letters Patent.

1. An hydraulic coupling of the type which transmits power. in relation to the quantity of working. fluidthereimmeans for providing a flow offluid. through said coupling, means responsive to the temperature of the fluid within the conpling: for rapidly increasing the flow of fluid from said. coupling; a: fluid inlet to the coupling having a variable restriction therein and temperaturesresponsive means operatively connected to. said restrictionfor regulating the area thereof as a direct function of the temperature of the fluid. discharged from the coupling.

2; hydraulic. coupling for transmitting power; said: coupling-having a casing, a ring surrounding the casing, said ring being of a material having a greater coeflicient of expansion than said casing, passages for the removal of working fluid from said coupling when expansion ofsaid ring occurs and means responsive to the temperatureof the removed fluid-for controlling fluid flow to said coupling.

3. An hydraulic coupling for transmitting; power, said coupling havinga casing, a ring surroundingithexcasing, said-ring being of a material havin a greater coeflicient of expansion than said. casing; passages: for: thev removal of working fluid from said coupling when expansion of said ring occurs, a bimetallic switch against which working fluid? flowing from said coupling impinges anda solenoid valve responsive tothe bimetallic switch for controlling fluid flow to. said coupling.

4'. In apparatus for controlling the temperature of the fluid within the working chamber of a hydraulic coupling, a casing having a groove around its periphery, a ring mounted in said groove, said ring being of a material having a greater coeiiicient'of expansion than. said casing, means to permit the flow of fluid from said coupling, means controlled by said ring to increase the flow of fiuidfromsaid coupling in accordance with an increasing temperature of the fluid within said coupling, and means responsive to the temperature of the fluid flowing from said coupling to increase the flow of fluid to said coupling.

5. In apparatus for controlling the temperature of the fluid within the working chamber of a hydraulic coupling, a casing having a groove around its periphery, a ring within said groove and surrounding; saidcasing, said ring being, of

a materialhavinga greatencoefiicient of; expansion than said. casing, means. to, permitthe fiow of: fluid from said coupling, means controlled by said ring to increase fluid flow from said coupling, in'accordance with an increasing temperature of" the fluid within said coupling, a fluid supply passagc tosaid coupling having a variable restriction therein, a bimetallic element against which. fluhl? flowing from said coupling impinges and. means responsive to said bimetallic element to increase the area of said restriction when the temperature of the fluid flowing from the coupling exceeds a predetermined limit.

6. In apparatusrior controlling. thetemperature of the fluid within the. working. chamber of a hydraulic coupling, a thermostaticelementsurrounding said. couplingcasing, passages to permit fluid flow. from said coupling and means. controlled by said thermostatic element to. in. crease the fluid flow from said coupling incase. of overheating, in. combination with a second. thermostatic element responsive to the temperature of the fluid flowing from, said coupling, and a solenoid valve controlled by said second element for regulating the flow of fluid to said. coupling.

7. In apparatus for controlling the temperature of. the fluid within the working chamber of a hydraulic coupling, a ring mounted. in av grooveon the outer surface of the coupling casing, said. ring being of a materialhaving. a, greater coeiiicient of expansion than said casing so that said ring will expand at a faster rate than said casing due to an increase in, thetemperarture of the coupling fluid bleeds, permitting a. flow of fluid from said coupling, passages controlled by said. ringfor increasing the fluid flow from said. coupling in accordance with a temperature rise ofv said fluid, a thermostatic switch. against which fluid flowing from said. coupling impinges and an electrically actuated valve. re.- sponsive to said switchfor regulating fluid flow to said coupling in accordance with the tempera.- ture rise of said fluid flowing from said. coupling.

8. An hydraulic coupling adapted to bev filled with. a. working fluid, a casing for, the coupling, said casing having a groove on its periphery with. bleed portsin said-groove, a ring mounted in saidv groove and covering saidportssaidring having. substantial clearance with the; i sides of: said. groove; radial passages in, said ring aligning with said casing ports and being; smaller in diameter than said ports, said passages and ports permit? ting fluid flow from the, coupling during normalv operation or" said coupling, said. ring being of a material having agreater coefflcient of expansion thansaid. casing so that fluid flow from said passages and ports will be supplemented by fluid flow around said ring as coupling temperature increases.

PHILIP P. NEWCOMB.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED" STATES PATENTS Number Name Date 2,405,135 Butzbach Aug. 6, 1946 2,421,501. Hasbrouckv June 3, 1941 2,459,734. McCraoken Jan. 18., 1949 FOREIGN PATENTS.

Number Country Date;

375;7.50" Italy Oct. 23,, 1939 

